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Best Management Practice #12: Laboratory and Medical Equipment

Equipment used in hospitals and laboratories can use significant amounts of water, offering the opportunity for substantial water savings by making a few small changes to how and when the water is used by the equipment.

Water-consuming equipment in laboratories and medical facilities include water purification systems, sterilization and disinfection systems photographic and x-ray equipment, vacuum systems, glassware washers, and vivarium equipment.

Operations and Maintenance

The following operations and maintenance options help federal agencies maintain water efficiency across facilities.

  • Establish a user-friendly method to report leaks and fix them immediately.
  • Encourage cleaning or custodial crews to report problems.
  • When performing maintenance, replace worn parts and adjust mechanisms to ensure water consumption continues to meet manufacturer guidance.
  • Shut off units that are not in use or install an automatic shut-off feature if it does not interfere with the unit's normal operation.
  • Check solenoids or automatic shut-off valves regularly to ensure that they are working properly. Verify that water is not flowing when equipment is in standby mode.
  • Install a pressure-reducing device on equipment that does not require high pressure. Lowering the pressure can reduce water use.
  • Set equipment to the minimum flow rates acceptable or recommended by the manufacturer and post signs near equipment to increase employee awareness and discourage tampering with equipment flow rate.
  • Run washing equipment only when full. Use newer, cleaner rinsing detergents, and reduce the number of rinse cycles whenever possible.

Retrofit and Replacement Options

The following retrofit and replacement options help federal agencies maintain water efficiency across facilities. These options span:

Water Purification Systems
  • Evaluate laboratory requirements for high-quality water, including the total volume and the rate at which it will be needed, so that the system can be properly designed and sized.

  • Choose systems with a higher recovery rate (the ratio of filtered purified water to the volume of feed water). Some proprietary systems claim recovery rates up to 95%. Conventional reverse osmosis systems have recovery rates between 50% and 75%.

  • Consider reusing concentrate produced by reverse osmosis treatment systems for nonpotable applications such as in bathroom commodes. Water quality should be monitored to avoid fouling other systems.

  • Determine the quality of water required in each application. Use the lowest appropriate level of quality to guide the system design. For example, reverse osmosis units should be used only in processes that require very pure water.

  • Evaluate water supply quality for a period of time before the water purification system is designed. This evaluation allows designers to accurately characterize water supply quality and helps them determine the best method for attaining the required quality level.

  • Find techniques for optimizing reverse osmosis systems.

Disinfection/Sterilization Systems
  • Replace older inefficient equipment with equipment designed to recirculate water or that allows the flow to be turned off when the unit is not in use, or both.

  • If purchasing new equipment is not feasible, consider purchasing a water efficiency retrofit kit. Many are now available for older units. These kits reduce water use by controlling the flow of tempering water or by replacing the venturi mechanism for drawing a vacuum. Tempering kits sense the discharge water temperature and allow tempering water to flow only as needed.

  • Install a small expansion tank instead of using water to cool steam for discharge to the sewer. Check with the manufacturer to make sure this will not interfere with the unit's normal operation.

Photographic and X-Ray Equipment
  • If the purchase of new equipment is not feasible, adjust the film processor flow to the minimum acceptable rate. Install a control valve and flow meter in the supply line to monitor the flow rate if necessary.

  • Recycle rinse bath effluent as make-up for the developer/fixer solution.

  • When purchasing new equipment, chose digital equipment.

Vacuum Systems
  • For liquid-ring vacuum pumps that continuously discharge water required to generate a vacuum, consider implementing a recovery and recirculating system. Find information on this retrofit in the WaterSense at Work best management practices.

  • When purchasing a replacement or new vacuum pump, chose a “dry” vacuum pump that does not use water to create the seal in the pump to generate the vacuum. Also consider using an air-cooled system that eliminates all water requirements.

Glassware Washers
  • For existing equipment, install a water recycling system for glassware washer wastewater.
  • When purchasing new equipment, chose systems that adjusts that water supply for the load size, provides rinse cycle options, and recycles the rinse water in the next cycle.
Vivarium Equipment
  • Replace older inefficient cage and rack washers with more efficient models. Look for models that recycle water through four cleaning stages using a countercurrent rinsing process. In countercurrent rinsing, the cleanest water is used only for the final rinsing stage. Water for early rinsing tasks (when the quality of rinse water is not as important) was previously used in the later stages of rinsing operations.
  • Retrofit existing cage and rack washers to make use of the countercurrent flow system to reuse final rinse water from one cage-washing cycle in earlier rinses in the next washing cycle.
  • Use tunnel washers for small cage-cleaning operations.
  • Sterilize and recirculate water used in automatic animal watering systems instead of discharging water to the drain.
  • Consider using alternative water such as process discharge or harvested rainwater for vivarium equipment. Find more information on the alternative water sources best management practice.